Status and trends of landbird populations in the Northern Colorado Plateau Network: 2022 field season

Roberts, Samuel; Tymkiw, Elizabeth; Ladin, Zachary; Shriver, Greg

doi:10.36967/2299435

In 2022, the University of Delaware, in cooperation with the National Park Service (NPS), completed the seventeenth year of a habitat-based landbird monitoring program in park units of the Northern Colorado Plateau Network (NCPN). This program is designed to provide rigorous population trend data for most diurnal, regularly occurring breeding landbird spe-cies throughout the network. This population information is useful for land managers and supports the National Park Service’s goal of long-term monitoring of biological indicators for network parks. In 2022, university biologists surveyed all 45 survey locations within 11 NPS units. Fifteen transects were located in each of the three habitats of interest: low-elevation riparian, pin-yon-juniper, and sagebrush shrubland. Each location was surveyed once. In addition to the habitat-based surveys, four point counts and an area search were conducted at Pipe Spring National Monument using a modified monitoring design. Over 17 years of data collection, 15,777 point-count surveys have been conducted in 11 NCPN units, detecting 179 unique species. During the 2022 field season, 638 point-count surveys were conducted, detecting 117 unique species. A total of 6,245 individual birds of 117 unique species were recorded. One new species was detected for this monitoring pro-gram: a Lewis’s woodpecker (Melanerpes lewis) in Black Canyon of the Gunnison National Park. In addition, the following birds were detected in the following parks for the first time in this monitoring program: lazuli bunting (Passerina amoena), Black Canyon of the Gun-nison National Park; summer tanager (Piranga rubra), Arches National Park; MacGillivray’s warbler (Geothlypis tolmiei), Bryce Canyon National Park; red-naped sapsucker (Sphyrapicus nuchalis), Curecanti National Recreation Area, and Lincoln’s sparrow (Melospiza lincolnii), Zion National Park. Using data from 2005 to 2022, 118 population-density trends were estimated across the three habitats. Fifteen of the estimated density trends were significant (p-value <0.05), including seven negative trends: • mourning dove (Zenaida macroura) and white-throated swift (Aeronautes saxatalis) in low-elevation riparian; • mourning dove, white-throated swift, and mountain bluebird (Sialia currucoides) in pinyon-juniper; and • rock wren (Salpinctes obsoletus) and western meadowlark (Sturnella neglecta) in sage-brush shrubland habitat. There were also eight positive trends: • hairy woodpecker (Leuconotopicus villosus) in low-elevation riparian; • lazuli bunting (Passerina amoena), yellow-rumped warbler (Setophaga coronata), and vesper sparrow (Pooecetes gramineus) in pinyon-juniper; and • house finch (Haemorhous mexicanus), western tanager (Piranga ludoviciana), Grace’s warbler (Setophaga graciae) and lark sparrow (Chondestes grammacus) in sagebrush shrubland habitat. There were sufficient sample sizes to estimate the densities of 61 species in at least one of the three habitats surveyed.

Status and trends of landbird populations in the Northern Colorado Plateau Network: 2022 field season

Series

Collections